01 - Toss cabbage, red onion, cilantro, lime juice, and a pinch of salt in a bowl. Set aside to allow flavors to meld.
02 - Combine avocado, sour cream, cilantro, lime juice, garlic, salt, and pepper in a blender or food processor. Blend until completely smooth and creamy. Taste and adjust seasoning as needed.
03 - Whisk together flour, cornstarch, baking powder, salt, pepper, and paprika in a bowl. Gradually whisk in the sparkling water until a smooth batter forms.
04 - Pour oil into a deep skillet or pot and heat over medium-high heat to 350°F.
05 - Pat fish strips dry with paper towels. Dip each strip into the batter, allowing excess to drip off, then carefully place in the hot oil. Fry in batches until golden brown and crispy, about 3-4 minutes per batch. Transfer to paper towels to drain.
06 - Place a portion of fried fish in each warm tortilla. Top with slaw and a generous drizzle of avocado crema. Garnish with additional cilantro if desired and serve with lime wedges on the side.